1. Field of the Invention
This invention relates to a space simulation system designed to simulate weightlessness. More particularly, it relates to such a simulation system in which disadvantages associated with pressure levels that produce bends are avoided. It also relates to a weightlessness simulation process which is desirably practiced with the system.
2. Description of the Prior Art
It has long been recognized that astronauts should receive training in a weightless or simulated weightless environment before they are sent into outer space. One way that this has been accomplished is by providing a training compartment in an aircraft that flies in a curved trajectory to match the acceleration of a falling body in the Earth's gravity, but this approach allows weightlessness to be achieved for only short periods of time, such as a minute or two, and is very expensive. Another approach that has been suggested in the prior art is to provide a mechanical device giving the astronaut six degree freedom of movement, as disclosed in U.S. Pat. No. 3,516,179, issued June 23, 1970 to Dane.
Simulators for the vacuum environment of outer space are also known in the art. Such simulators are disclosed in, for example, U.S. Pat. No. 3,010,220, issued Nov. 28, 1961 to Schueller and U.S. Pat. No. 3,534,485, issued Oct. 20, 1970 to Simpson et al, but these simulators do not make any provision for the weightlessness of outer space.
More recently, astronauts have been simulating weightlessness on the ground by wearing a pressurized space suit in a pool that appears similar to a large indoor swimming pool. Such a simulator is described in "Self-Contained Neutral-Buoyancy Suit", NASA Tech Briefs, January/February 1986, page 90. The differential pressure between the inside and outside of the space suit must be maintained at the same level that will be employed in outer space for the suit to operate with the same flexibility and handling characteristics that it exhibits in outer space. For the forthcoming space station, that pressure differential has been established as 8.3 PSI, which is measured at the heart in the case of a pool simulation.
When an astronaut performs simulation exercises in a pool, the internal suit pressure must be greater than atmospheric in order to obtain the proper pressure differential. The internal pressure is high enough in this environment so that the astronaut must undergo decompression in the same manner as a diver in order to avoid bends. For safety reasons, a large standby medical/safety team is required whenever such pool simulations are being carried out. While realistic simulation is possible using the pool, extra time and a chamber are required for the decompression, and extra manpower is required for the medical/safety team.